I think that you got most of it right; however as you say it was quite messy and I did have difficulty in decifering it where it was squashed and I struggled with telling which # mark was which in some places and I couldn't always read the associated number.
To be honest you made a reasonable job of maxiimising the use of space on the sheet and to have split the diagram over two woukld have cost you time re the overlapping area between them.
Actually I think that drawing diagonal lines (and yes I think using a ruler) from say 162 back to 1136/42 and from 164 back to 134 would have permitted these to have een closer and therefore the area 122 back to 118 would not be so squashed.
It would also help "see at a glance" as it isn't intuitively obvious what is going on in your diagram- however the slight diagonality of the lines behind 164 back to 134 and to 142 do actually help quite a bit. The very angular approach is something done for CAD convenience only and certainly not helpful in handawn diagrams for IRSE Exam.
I rather lost you with the dashed lines in this area annotated #2 and #3; the quoted tracks look like approach release for signal 162 and 164 yet they don't seem to be associated closely with those signals. From the look of the diagram, it looks like you may have had a bit of a brainstorm (perhaps it is the recent heatwave having an effect!) whilst doing it- what I see just doesn't make sense but it is evident from the rest of the chart that you know what you are doing - hence it leaves me confused how to interpret.
You are saying that 142 displays Y+SI"M" up to 164 at Red but the dashed line seems to be "in parallel" to it and would surely suggest 142 shows the same aspect up to Y, but only when the intervening track is occupied (that would of course replace 142 to red).
The only other thing that I can imagine is that you were thrown by a 3 aspect signal reading up to a 4 aspect- I would generally expect that 142 would show G up to 164 at Y, YY or G but this would need to be justified by checking that from the attainable speed appraching 164 that there is indeed enough distance to brake from the single Yellow to the Red. This is something I would state as an assumption, but given that the speed over the points is low, that a train cannot accelerate until its rear end is clear of the restriction and they don't accelerat like cars thn it seems a good call.
I just wonder whether you were trying to say that if 164 couldn't display at least Double Yellow then it would have to be approach released from Red if approached from 142. If so you made a mess of showing it! You should have shown the dashed line from 164's Red to its Yellow and explained the trigger condiiton in the note; as far as 142 is concerned its Yellow reads always to 14 at Red, the fact that it might then change in some conditions is no concern of 142.
162A(S)
I think that I would categoorise this as a running signal and hence would have shown disappearing onto the Docks Branch- there may perhaos be a fixed distant board to read up to.
#4
As far as the flashing aspect is concerned, yes definitely unusal in that the "164 at Yellow and pos 4" is an aspect that is only ever shown as the train approaches the junction signal before it steps up to a better aspect. Can't think that I have ever met such a beast- an IRSE special as far as I know. Probably there is one somewhere and a very sad person knows where and the signal numbers involved.
You did not show that there is also a "fallback" MAR for any MAY-FA route (for use when the routes are not set early enough otr there is a failure of the flasher etc.) I didn't attempt to add to diagram given space constraints, but look at the 2008 eaxample when I added the MAY-FA to your existing MAR to see the idea.
#1
Actually you didn't need this assumption- to my mind it says as much in the notes box in bottom left of diagram.
ROL at EK/EH
I think this confused you- it is actually a full overlap beyond 142 (there is no other overlap here, 122 does not have a D(W)). It is only a ROL from the other direction.
122D(M)
This particular route box entry, unusually, just says "Main" rather than quoting the relevant aspects. Actually I think that I would only have it showing Y or G for this diverging route as the YY not needed since the Yellow at 142 gives plenty of braking distance for the speed involved. Can't help thinking that is why they presented like this.
122 approach release
I reckon that you actually know this but I did have difficulty extracting this from what you actually drew. I know you were short of space but to show both the "Y+pos1 for the R with ROL at 134" and the "Y+pos1 for the R with full overlap at 134" on the same vertical dotted line was a mistake.
It also looks as if you got the #6 and #7 the wrong way around (perhaps that splodge is actually a second #6 above the #7 I can't tell). I would always recommend showing each separate trigger condition as a separate dotted line with associated # note.
Given what I have written above you didn't need the reease to Y+pos4, but assuming you did you'd have done better joining the similar release for tthe Y+pos1 to it horizontally. However to be very picky, I always like the more restrictive release to be the closer to the signal....
Also (and this is probably because I am from the Western that had "delayed yellows" implemented at aspect level rather than separate Warning class routes), I find it helpful to show the aspect either as "R/Y" or "DY" instead of "Y" since it sticks out better and clearly depicts that its signalling meaning is different (even if the driver just sees a Yellow and has no means of knowing WHY it has just changed).
So overall it was probably a good learning exercise and despite the comments above gives a generally good impression- it was really just those dashed lines in the middle of aspect sequence lines which detract significantly.
It is unlikely of course that an aspect sequence question of this form will arise in 2013. On a layout like this it is hard to see how to prioritise; I am afraid that this may be a case when "I've started so I'll finish" may have to apply- you could take so long trying to economise that it could actually have been finished off in less. That does not mean though I'd just carry on; I'd stop when the time ran out and I needed to go onto the next question, hoping that I could shave a few minutes off that one to have time to return. Attempying to prioritise within the aspect sequence question itself is what I think would be counterproductive- you'd lose time thinking, possibly make uncccessary errors etc. Just start at the last signal(s) at the edge of the plan and work back, ensuring a suitable aspect sequence on the approach to any red, from all the possible approach directions and do this in an ordered manner; when run out of allocated time, move on.
To be honest you made a reasonable job of maxiimising the use of space on the sheet and to have split the diagram over two woukld have cost you time re the overlapping area between them.
Actually I think that drawing diagonal lines (and yes I think using a ruler) from say 162 back to 1136/42 and from 164 back to 134 would have permitted these to have een closer and therefore the area 122 back to 118 would not be so squashed.
It would also help "see at a glance" as it isn't intuitively obvious what is going on in your diagram- however the slight diagonality of the lines behind 164 back to 134 and to 142 do actually help quite a bit. The very angular approach is something done for CAD convenience only and certainly not helpful in handawn diagrams for IRSE Exam.
I rather lost you with the dashed lines in this area annotated #2 and #3; the quoted tracks look like approach release for signal 162 and 164 yet they don't seem to be associated closely with those signals. From the look of the diagram, it looks like you may have had a bit of a brainstorm (perhaps it is the recent heatwave having an effect!) whilst doing it- what I see just doesn't make sense but it is evident from the rest of the chart that you know what you are doing - hence it leaves me confused how to interpret.
You are saying that 142 displays Y+SI"M" up to 164 at Red but the dashed line seems to be "in parallel" to it and would surely suggest 142 shows the same aspect up to Y, but only when the intervening track is occupied (that would of course replace 142 to red).
The only other thing that I can imagine is that you were thrown by a 3 aspect signal reading up to a 4 aspect- I would generally expect that 142 would show G up to 164 at Y, YY or G but this would need to be justified by checking that from the attainable speed appraching 164 that there is indeed enough distance to brake from the single Yellow to the Red. This is something I would state as an assumption, but given that the speed over the points is low, that a train cannot accelerate until its rear end is clear of the restriction and they don't accelerat like cars thn it seems a good call.
I just wonder whether you were trying to say that if 164 couldn't display at least Double Yellow then it would have to be approach released from Red if approached from 142. If so you made a mess of showing it! You should have shown the dashed line from 164's Red to its Yellow and explained the trigger condiiton in the note; as far as 142 is concerned its Yellow reads always to 14 at Red, the fact that it might then change in some conditions is no concern of 142.
162A(S)
I think that I would categoorise this as a running signal and hence would have shown disappearing onto the Docks Branch- there may perhaos be a fixed distant board to read up to.
#4
As far as the flashing aspect is concerned, yes definitely unusal in that the "164 at Yellow and pos 4" is an aspect that is only ever shown as the train approaches the junction signal before it steps up to a better aspect. Can't think that I have ever met such a beast- an IRSE special as far as I know. Probably there is one somewhere and a very sad person knows where and the signal numbers involved.
You did not show that there is also a "fallback" MAR for any MAY-FA route (for use when the routes are not set early enough otr there is a failure of the flasher etc.) I didn't attempt to add to diagram given space constraints, but look at the 2008 eaxample when I added the MAY-FA to your existing MAR to see the idea.
#1
Actually you didn't need this assumption- to my mind it says as much in the notes box in bottom left of diagram.
ROL at EK/EH
I think this confused you- it is actually a full overlap beyond 142 (there is no other overlap here, 122 does not have a D(W)). It is only a ROL from the other direction.
122D(M)
This particular route box entry, unusually, just says "Main" rather than quoting the relevant aspects. Actually I think that I would only have it showing Y or G for this diverging route as the YY not needed since the Yellow at 142 gives plenty of braking distance for the speed involved. Can't help thinking that is why they presented like this.
122 approach release
I reckon that you actually know this but I did have difficulty extracting this from what you actually drew. I know you were short of space but to show both the "Y+pos1 for the R with ROL at 134" and the "Y+pos1 for the R with full overlap at 134" on the same vertical dotted line was a mistake.
It also looks as if you got the #6 and #7 the wrong way around (perhaps that splodge is actually a second #6 above the #7 I can't tell). I would always recommend showing each separate trigger condition as a separate dotted line with associated # note.
Given what I have written above you didn't need the reease to Y+pos4, but assuming you did you'd have done better joining the similar release for tthe Y+pos1 to it horizontally. However to be very picky, I always like the more restrictive release to be the closer to the signal....
Also (and this is probably because I am from the Western that had "delayed yellows" implemented at aspect level rather than separate Warning class routes), I find it helpful to show the aspect either as "R/Y" or "DY" instead of "Y" since it sticks out better and clearly depicts that its signalling meaning is different (even if the driver just sees a Yellow and has no means of knowing WHY it has just changed).
So overall it was probably a good learning exercise and despite the comments above gives a generally good impression- it was really just those dashed lines in the middle of aspect sequence lines which detract significantly.
It is unlikely of course that an aspect sequence question of this form will arise in 2013. On a layout like this it is hard to see how to prioritise; I am afraid that this may be a case when "I've started so I'll finish" may have to apply- you could take so long trying to economise that it could actually have been finished off in less. That does not mean though I'd just carry on; I'd stop when the time ran out and I needed to go onto the next question, hoping that I could shave a few minutes off that one to have time to return. Attempying to prioritise within the aspect sequence question itself is what I think would be counterproductive- you'd lose time thinking, possibly make uncccessary errors etc. Just start at the last signal(s) at the edge of the plan and work back, ensuring a suitable aspect sequence on the approach to any red, from all the possible approach directions and do this in an ordered manner; when run out of allocated time, move on.
(15-07-2013, 08:32 AM)dorothy.pipet Wrote: Another attempt at the 2006 Aspect Sequence chart.
I found this very complex - it exposed some holes in my knowledge, which is part of the benefit of doing these past papers. I think this also means it's rather messy, but given I wouldn't have time to re-draw it under exam conditions, I submit it for comments as is.
I would definitely not have got it all done in the time, perhaps I need to think about where to start in an exam, and which bits are less important if I don't have time to complete.
PJW
